JPS60176185A - Quantizing method of hand-written character and graphic - Google Patents

Abstract

PURPOSE:To enable quantization free from a character fluctuation and an inclination by extracting a temporary segment from inputted coordinate information and by considering the synthesization of adjacent temporary segments as one temporary segment if the difference in the temporary directional code of the adjacent temporary segments. CONSTITUTION:Coordinate information (a) obtained from a coordinate input device 1 is inputted to a temporary segmenting processing part 2, a candidate considered to be the segment is extracted and set to temporary segment information (b), which is inputted to a temporary directional code generating part 3. In accordance with the direction of the temporary segment, temporary directional code information (c) in 32 directions is generated and inputted to a segment synthesization processing part 4, which synthesizes the segment if necessary by utilizing the temporary directional code information (c) and outputs the final segment information (d). A directional code generating part 5 outputs directional code information (e) in eight objective directions in accordance with the direction of the segment. Provided that when directional codes of adjacent two segments are equal, they are synthesized in order to be one line segment, and one directional code shall be given.

Description

[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a pattern recognition device that uses the direction of a line segment in which a figure or a character is placed as a feature quantity, and in particular, it relates to a pattern recognition device that uses the direction of a line segment in which a figure or a character is placed as a feature quantity, and in particular, The present invention relates to a quantization method suitable for extracting features without being affected by gradients or slopes.

[Background of the invention]

Conventionally, pattern recognition devices such as figures and characters.

The direction of the line segments that make up the isomorphism or character is used as a feature quantity, or
Many methods are used as part of this. but,
When recognizing handwritten figures or characters using this method, there was a problem in that the number and direction of line segments could not be accurately extracted due to the effects of wobbling and inclination, which are characteristics of handwriting, and the recognition rate decreased. . In particular, it is important to remove the influence of fluctuation near the boundary (threshold) of the directional range when performing quantization.

As a method to solve this problem, the example shown in Nikkei Electronics, May 7, 1973 issue, pages 46-47, and the Proceedings of the 1986 Institute of Electronics and Communication Engineers National Conference No. 13
Examples include the one disclosed in No. 76.

The former is by expanding the tolerance range of the final quantization direction of the previously quantized part compared to other directions.
Reduces the effects of wandering.

However, this method has a drawback in that it is impossible to completely eliminate the influence of fluctuations near the boundaries of the quantization range because the tolerance range is fixed.

On the other hand, in the latter case, the quantization is performed twice by changing the boundary during quantization, and by considering either direction as a single line segment, the influence of the fluctuation of the line segment near the boundary is decreasing. However, since this method performs a complex process of composing the results of two quantizations, it is elegant to implement in hardware, and the disadvantage is that it does not completely eliminate the influence of the absolute direction of the input line segment. was there.

[Purpose of the invention]

SUMMARY OF THE INVENTION In order to overcome these drawbacks, it is an object of the present invention to provide a quantization method that is not affected by the fluctuation or inclination of input figures or characters.

[Summary of the invention]

The present invention extracts a temporary line segment connecting representative point sequences from input coordinate information, gives this temporary line segment a temporary direction code that is subdivided from the direction code used as a feature, and then , if the difference in the temporary direction codes of two adjacent temporary line segments is less than a predetermined value, they are considered to be included in the same line segment, and the composite of them is considered to be a single temporary line segment, and if the difference is more than a predetermined value If there is, it is possible to perform optimal line segmentation by sequentially performing processing to consider it as a different line segment, and then generate a direction code as a feature, regardless of the slope of the input figure or character. , which performs quantization without being affected by the fluctuations peculiar to handwriting.

[Embodiment of the Invention] Hereinafter, an embodiment of the present invention will be described in detail with reference to FIGS. 1 to 6.

FIG. 1 is a block diagram of one embodiment of the present invention.

In this embodiment, eight types of direction codes as shown in FIG. 2 are generated according to the direction of the components constituting a figure or character, and these are recognized as feature quantities. Coordinate information a obtained by the coordinate input device 1 is input to the temporary line differentiation processing section 2.

The temporary line differentiation processing unit 2 extracts candidates that are considered to be line segments from the input coordinate information.There are various methods for this, but for example, it uses the angle change of a curve connecting the input coordinates. There is a way. This is done by examining the distribution of angular changes and determining that the points where the angular changes are equal to or greater than a predetermined value are the boundaries of line segments. That is, this is a method in which the distance between two points where the angle change is equal to or greater than a predetermined value is defined as -. line segments. Regardless of which method is used, in this temporary line differentiation processing unit 2, since the input coordinate information a is of a handwritten figure or a character,
What should originally be considered a single line segment is often divided into more line segments due to line segment fluctuation.

The temporary line segment information obtained by the temporary line segmentation processing unit 2 is input to the temporary direction code generation unit 3, and temporary directions are generated in 32 directions O1 to O32 as shown in FIG. 3 according to the direction of the temporary line segment. Generate code. This temporary direction code information C is input to the line segment synthesis processing section 4.

The line segment synthesis processing section 4 synthesizes line segments as necessary using the board direction code clear side C, and outputs final line segment information d. From the line segment information d, the direction code generating section 5 outputs direction code information C for eight target directions as shown in FIG. 2 according to the direction of the line segment. However, if the direction codes of two adjacent line segments are the same, they are combined into one line segment and given one direction code.

The direction code matching processing unit 6 compares the direction code information e of one handwritten figure or character with the direction code information f registered in advance in the dictionary 7, and selects the figure or character that is judged to be the closest. Then, the graphic or character information g is output to the graphic/character display device 8, and the graphic or character information recognized by LFA is displayed on the graphic/character display device 8. Since many examples of these 6, 7, and 8 are known, detailed explanations will be omitted here.

Hereinafter, the processing contents of the line segment synthesis processing section 4, which is a feature of the present invention, will be explained in detail. FIG. 4 is a flowchart showing the line segment combining process. First, the difference in sheet direction code between the first temporary line segment and the second temporary line segment to which it is connected is calculated (step 402). However, this difference is not the difference in the direction code value itself, but the difference in angle, for example, the difference between 01 and 32 is assumed to be 1. If this difference is 3 or less, the first temporary line segment and the second temporary line segment are considered to be included in the same line segment, and the composite of these two is reused as one temporary line. Then, the board direction code for the temporary line segment is entered (step 406). Then, the same sheet direction code as described above is compared between this combined temporary line segment and the next temporary line segment, that is, the third temporary line segment. Next, when the difference in direction codes is 4 or more, in this case, the two temporary line segments are considered to be separate line segments, and the first temporary line segment is determined to be one line segment. Step 404)
, the board direction codes are again compared between the second temporary line segment and the next temporary line segment.

By continuing similar processing, the true line segment is determined.

FIG. 5 shows an example in which the processing described in section H below is performed.

(a) is a handwritten curve that has undergone the temporary line differentiation process, and Δ
It is composed of four temporary line segments from 1 to A4, and the board direction codes are 02, 03, 02. t.

It becomes. First, compare the plate direction codes of temporary line segments A1 and A2, and the difference is ], so these are considered to be included in the same line segment, and the composite of these is re-created as one temporary line segment. Let it be Δ5.

This Jl is (b). The board direction code of the temporary line segment A5 is 03. Next, when comparing the direction coats of temporary line segments A5 and A3, the difference is 1, so temporary line segment A5. Synthesize A3 and obtain the temporary public figure 6. The board direction code for 86 is 02
It is. This is (C). Next, temporary line segments A6 and A4
When compared, the board direction code difference is 8, so A6
are independent line segments. Furthermore, since A4 is the last temporary line segment, it is also treated as one line segment. In this way, the combination of four temporary line segments like (,) is
It is considered as two line segments as shown in (c).

As shown in FIG. 6, the line segment information is sent to the direction code generation section, which outputs the desired direction codes DI and D3, and sent to the direction code matching processing section 6.

Next, the effects of the embodiments of the present invention will be described.

First, it uses a two-step method in which after performing temporary line segmentation, line segment compositing processing is performed as necessary to determine the final line segment, so even long line segments with fluctuations can be combined into multiple line segments. It has the effect that it is not divided and short line segments are not overlooked.

In a method that performs line segmentation in one step, it is difficult to detect the difference between /M'i long line segments and wobbling.In general, when trying to accurately extract long line segments with wobbling, short line segments are overlooked, If an attempt is made to extract short line segments without overlooking them, the problem is that long line segments with fluctuations are divided into multiple line segments. In this example, this drawback was overcome by performing line segmentation in two stages.

Second, even if a handwritten figure or a line segment constituting a character exists near the border of slanting, it can be slanted without being affected by the unsteadiness peculiar to handwriting.

The effects of the temporary line segment sequences A1-A4 and B1-B4 as shown in FIG. 6 will be described below. The direction codes finally obtained are eight directions as shown in FIG. In FIG. 6, TI, ]"2.1'3 is the boundary of direction coding. The board direction code of the temporary line segment sequence 13], ~B4 is 08
-09-08-16, and when line segment synthesis processing is performed, B
The tentative line segment examples 1 to 133 become one line segment, and the final direction code becomes D3-D5 since continuous line segments with the same direction code are regarded as one line segment. Regarding this temporary line segment sequence, a similar result can be obtained by a method in which the final code is generated in one step. On the other hand, the board direction code of the temporary line segment sequence Al-A4 is 02-03-02-]O, and if line segment synthesis processing as shown in the present invention is performed.

As shown in FIG. 5, there are two line segments, and the final direction code is DI-D3. However, when the final code is generated in one step for this temporary line segment sequence, D 1-D
2-D 1-03, and the temporary line segment sequences A1~Δ4 and 81~
Although B4 has the exact same shape with only a 60" change in direction, the number of line segments is different. In other words,
The temporary line segment sequence A1-A4 near the boundary is affected by the fluctuation. On the other hand, in this embodiment, since the final line segment is determined based on the difference between the temporary direction codes of two adjacent temporary line segments, the influence of the absolute direction of the input line segment (X-conversion error) does not exist at all.

In the embodiment of the present invention, the temporary direction code is 32 directions and the final direction code is 8 directions, but the number of directions may be changed as appropriate depending on the situation. In addition, the threshold value of the temporary direction code difference (Fig. 4,
d) in 402 may also be changed as appropriate. Furthermore, it is also possible to sample the input coordinates at regular intervals without performing the temporary line segmentation process, treat the sampling points as one temporary line segment, and perform subsequent processing in the same way.

The embodiment of the present invention performs 1Mt final direction code matching processing to recognize figures or characters, but it can also be used as a single figure formatting function just by displaying the result of line segmentation. .

〔Effect of the invention〕

According to the present invention, regardless of the input handwritten figure or the inclination of the character, in other words, the input hand IFI
Regardless of the absolute direction of the IIA component, line segments can be quantized without being affected by the fluctuations peculiar to handwriting.
The recognition rate of the handwriting recognition device can be increased.

[Brief explanation of the drawing]

FIG. 1 is an overall block diagram of an embodiment of the present invention, FIG.
FIG. 3 is a direction code diagram of an embodiment of the present invention, FIG. 4 is a flowchart of an embodiment of the present invention, and FIG. 5 is a diagram. FIG. 6 is an explanatory diagram of processing according to an embodiment of the present invention. 1... Coordinate input device, 2... Temporary line differentiation processing unit, 3.
... Temporary direction code generation section, 4... Line segment synthesis processing section, 5
... Direction code generation section, 6 ... Direction code matching processing section 2nd day 3 7 3rd eye 3rd mouth 5th day 6th concave

Claims (1)

[Claims] 1. In a method for checking handwritten characters and figures using the direction of a line segment as a feature quantity. A representative point sequence is extracted from the input coordinate information, a temporary line segment connecting this point sequence is subdivided by the direction code used as a feature quantity, and a temporary direction code is given to the temporary line segment. The direction code of is compared with the direction code of the previous temporary line segment, and if the difference between the codes is less than a predetermined value, it is determined that the two line forces are on the same straight line, and the two codes are By sequentially processing the synthesized line segment to create another temporary line segment based on a predetermined value, the final line segment is obtained and used as the feature amount. A method for quantizing handwritten character figures, characterized by quantizing them by giving a direction code.